Organosiloxanes



May le, 195o H@ A, CLARK 2,507,516

oRGANosILoxANEs A' Filed March 19, 1949 HAROLD A. CLARK Patented May 16, 1950 ORGANOSILOXANES Harold A. Clark, Midland, Mich., assignor to Dow Corning Corporation, Midland, Mich., a corporation of Michigan' Application March 19, 1949, Serial No. 82,415

10 Claims. (Cl. 26o-46.5)

The present invention relates to new organosilicon compositions and their production.

The present organosilicon industry is based upon siloxanes which are materials in which the silicon atoms are linked through oxygen atoms. Another type of silicon compound is one in which the silicon atoms are linked directly to each other. Still a third type is one in which the silicon atoms are linked by organic radicals. The present application is concerned with compositions which contain both siloxane and methylene linkages.

In accordance with the present invention, these new organosilicon compositions are produced by hydrolyzing compounds of the type in which each R represents a radical of the group consisting of alkyl and monocyclic aryl radicals and each X represents a halogen atom.

'Ihe compositions of the present invention have the general formula asicmgin [g l l where n is an integer having a value of at least 3 and each R. is a hydrocarbon radical of the group consisting of alkyl radicals, such as methyl to octadecyl, and monocyclic aryl radicals, such as phenyl, tolyl and xylyl. Where n has a value of three, the composition produced is cyclic and of a crystalline nature. The general formula of this crystalline composition is shown in Fig. 1

of the accompanying drawing which is a diagram- I CHsClzSiCHzSiClzCI-Is may be prepared by reacting CHsCizS'iCHzSiCla with methyl Grignard reagent in amount sumcient to replace one of the chlorines with a methyl radical.

After the preparation of the reactant it may be diluted with ether, hydrolyzed and 65 condensed. Two layers are formed, one aqueous and the other an ether solution of the hydrolyzate. A deposit of crystals is separated from the ether solution. This may be removed by ltration. The balance of the hydrolyzate is removed by evaporation to form a varnish type of product. Alternatively the ether may be removed without adding any other solvent to produce a thermoplastic resin.

The identity of the compound [C HxiCHaiCHz] was proven by infrared spectroscopy. The method used is described in Wright and Hunter, J. A. C. S., vol. 69, page 803. In this method the spectrum of the solvent is compensated for so that no bands for the solvent appear. By the method of preparation it is known that the polymer units are The infrared spectrograph is shown in the accom-v panying drawing.

In the range from 2 to 7.6 a. a solution of 100 milligrams of the compound in 10 cc. of carbon tetrachloride was employed. 'In the range from '7.6 to 14 u, a solution of 150 milligrams of the compound in 10 cc. of carbon disulfide was employed. A sample cell one mm. thick was used.

The lack of a band at 2.95 ,l shows that there `is yno hydroxyl in the compound. Accordingly the compound is completely condensed. The bands at 3.4 and 7.9 a are related to methyl radicals on silicon. That at '7.1 u shows hydrogen on carbon. The bands at '7.4 and 9.5 ,L show methylene radicals bonded to two silicon atoms. That at 9.2 a shows the cyclicv structure (SiCHzSiO) and weather resistant coatings for boilers, stacks, ovens, and other hot metal surfaces.

The following examples illustrate the method oi the present application.

Example 1 Fifty parts by weight of 2,2,4,4 tetrachloro- 2,4 disilapentane, ClzCHaSiCHaSiCHaCla, was diluted with 99.6 parts of ethyl ether and the solution poured onto cracked ice. The ether hydrolyzate solution after a time started depositing crystals of A CHICHQOH; l l

which were separated by nltration. More of this crystallized upon concentrating the solution. The residue was a resinous material, which is useful as a varnish.

The crystalline product sublimed at 175 C. It was very soluble, in ether, acetone, ethanol, and butanol. The freezing point of the sublimed material is 199 C.

Example 2 formula C RiiCHisliR in which each R is a radical of the group consisting of alkyl and monocyclic aryl radicals and n is a positive integer having a value of at least three.

2. Organosiloxane compositions having the formula einem HislicHi i i in which n is a positive integer having a value o! at least three.

3. Organosiloxane compositions having the formula CnHsAiCHISiCHx i i i in which n is a positive integer having a value of at least three.

4. Organosiloxane compositions having the formula mmiomslicm,

in which n is a positive integer having a value of at least three.

5. Organosiloxane compositions having the formula Rsicmeiia .l l l s in which R is a radical of the group consisting y of alkyl and monocyclic aryl radicals.

the

6. An organosiloxane composition having the formula CHsiC HiC HI i l 7. The method which comprises hydrolyzing a compound of the type RXzSiCHzSiXzR. in which each R is a radical of the group consisting of alkyl and monocyclic aryl radicals and each X is a halogen atom, and condensing the hydrolyzate, whereby there is produced an organosiloxane composition of the type in which n is a positive integer having a value of at least three.

8. The method in accordance with claim 'l in which all of the Rs are methyl radicals.

9. The method in accordance with claim 'l in which some of the Rs are methyl radicals and the remainder are phenyl radicals.

10. The method in accordance with claim 7 in which al1 of the R's are phenyl radicals.

HAROLD A. CLARK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,352,974 v Rochow July 4, 1944 2,381,000 Patnode et al. Aug. 7, 1945 2,467,858 Sage Apr. 19, 1949 OTHER REFERENCES Bluestein: Journ. Amer. Chem. Soc., voi. 70. Sept. 1948, pp. 3068 to 3071. 

1. ORGANOSILOXANE COMPOSITIONS HAVING THE FORMULA 